Apparatus for testing insulation



NOV. 16, 1937. w 1 2,099,112

APPARATUS FOR TESTING INSULATION Original Filed Oct. 29, i951 3 Sheets-Sheet l ATTORNEY APPARATUS FOR TESTING INSULATION Original Filed Oct. 29, 1931 3 Sheets-Sheet 2 I HWENT R H/LL Kiw WM A 770ENE) Nov. 16, 1937.

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Original Filed Oct. 29,- 1931 3 Sheets-Sheet 3 Q&&

A r m/v5 x such as exposure of the wire or conductor. or in- Patented Nov. 16,

1 UNITED STATES PATENT OFFICE.

2,099,112 srrsm'rus ron'rns'rma INSULATION Walter M. Hill, Randallstown, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New I03 Application October .29, 1931, Serial No. 571,811 Renewed January 26, 1937 s Claims.

Thisinvention relates to an apparatus for testing insulation and particularly to an apparatus for testing and inspecting rubber covered or insulated electrical wires or conductors.

5 The objectot this inventionis to provide an improved method and apparatuswhich will efll- Y ciently and rapidly test the insulation on elec.- a

-20 Fig. 1 isasideelevation oi a testing apparatus embodying the invention, and

' Figs. 2 and 3 combined constitute a wiringdiagram of the electrical sy'sten embodied, in the testing apparatus or the invention. r 28 In the illustrated apparatus the insulated wire or conductor to be tested is arranged so that in passing through the testing unit or electrode it will complete an electrical testing circuit of predetermined voltage and energize suitable indicating means when there is 'a defect in the insulation,

'sufliciency of the insulation for any reason to withstand the voltage of the testing circuit. The distributor mechanismis also included electrically dicate the exactposition or the defect in the insulation so that the detective section'ot the wire or conductor can-be repaired or removed therefrom. The countermechanism is arranged to indicate the length or the wire or conductor which has been tested as well as closingan electrical circult to an indicating means when 'a predetermined length of the wire oreonductor has passed therethrough, and simultaneously to cause the breaking of an electrical circuit to stop the apparatus. r

g In the drawings, the usual form of supply reel l isshown having wound thereuponins ulated to shaft l2 mounted for rotation in the supporting stand' l3, which is provided with a spring-pressed paddle brake it for-preventing overrunning of the wire or conductor l I. in order to rapidly stop in thissametesting circuit and is adaptedto inwire or conductor II to be tested and iss'ecured when a defect is encountered in the wire or conductor, a braking arrangement is provided consisting of a brake shoe l5 and co-operating brake drum [8 on the shaft l2, which is released by a solenoid l1, included in the motor circuit to be hereinafter described. when the solenoid is deenergized, due to the breaking of the motor circult automatically or manually by the operator, the spring l8 will operate the brake to stop the rotation of-reel III by forcing the brake shoe l5 into engagement with the brake drum I8 oi the shaft l2. r

The insulated wire or conductor II is threaded through the apparatus from reel It! by passing it over sheave l9, through the testing unit or electrode 20, which is'prei'erablyiormed with upper and lower testing channels. The wire or conductor ll, after passing through the upper channel 2|, passes around sheave 22 through the lower testing channel 23 and around s'heave 24. A form of testing unit or electrode is shown in detail in Patent No. 1,952,582, dated March 27, 1934, wherein the applicant is a joint inventor with Malcolm C. Cary;

From thetesting unit or electrode the wire is 25 passed through a counter or measuring device 25.

f This counter is provided with a series 01' contact wheels 26, 21, 2B and 29, between which the wire is passed. The'wheel 28 is mounted upona shaft,

which operates the counter mechanism-to indicate' the number oi! ieet oi. wire passing through the apparatus. The counter mechanism is shown schematically in Fig. 2 having contact members arranged in an electrical system to automatically stop the apparatus without disturbing the testing circuit when a predetermined length of .wire has been passed therethrough,-which is usually slightly lex than the desired coil length, and, for-purposes of illustration, the counter might be set to "stop. the apparatus at 990 feet. The counter mechanism is electrically connected to a signal .lamp 3|, which is illuminated when this predetermined length of wire has passed therethrough,

and remains lighted until the' operator manually In order to distribute the wire upon the takeup reels evenly in layers, a reciprocable distributor 32 is provided through which the wire passes from the counter. 'I'hisdistributoris provided with a comparatively short testing unit or elect ade included in the testing circmmh wuing a means for definitely locating a defect in the wire being tested, 7

In'order that the wire to be tested be drawn through the apparatus a motor driven take-up 10 suitable clutch mechanism, while the other reel is having the coil removed therefrom manually A treadle mechanism 39 disby the operator. connects the driven reel from the motor and releases the clutch mechanism to permit manual revolving 6F the saddle to place the empty reel in place for coiling, as shown in the patent to Malcolm 'C. Cary No. 1,881,018, dated October 4,

A solenoid brake 48 similar to the brake described in connection with supply reel 18 is provided for the motor 31 and is connected into the motor circuit to be operated in the same manne as the brake for the reel l8.

The operating electrical equipment is located for convenience within an enclosure 4| beneath the table or support 42 for the testing unit and counting mechanism and within the base 43 of the support for the reeling mechanism 33.

To prepare the apparatus for testing, it is necessary to place the electrical system in operation before threading the wire or conductor through the machine, so that the solenoid brakes can be released and the first length of wire or conductor leading from the supply reel l8 to the take-up reel 35 will be subjected to test. To prepare the apparatus for the threading, the main switch 44 is closed, furnishing, for example, 440 volts 3 phase service from the supply lines to the motor circuit 45 and 110 volts single phase service to the primary of the'testing circuit 46 and counter circuit 41 through the supply transformer 48. .This supply transformer 48 will act 'as an insulation transformer, permitting parallel operation of a series of testing machines. A means such as the indicating lamp 49 indicates that the main switch .44 is closed and the apparatus is con- Y nected to the supply lines; The lamp 49 is connected into the circuit through its transformer 58. When the main switch44 is closed, the 50 counter transformer 51 and the counter interlock transformer 52' are excited to furnish, for example, 110 volts service for the coil 53 of the length relay 5i and the coil 55 of the length interlock relay 56. These transformers 5| and 52 act as 55 insulation transformers to prevent the counter,

mechanism-25 from operating the fault relay.

Before the wire or conductor l I can be unwound manually from supply reell8 and threaded through the electrode and counter device, it is necessary to release the solenoid operated brake on the supply reel l8, and for this purpose two switches 51 and 51 are provided, shown in -the form of foot operated switches, which when pressed complete a circuit through the supply reel brake solenoid l1 to release the brake shoe l5 so that the wire H can be drawn from the supply reel l8, threaded through the apparatus; as shown in Fig. 1, and the end thereof attached by a grounding clamp (not shown) to the take-up reel 70 35. The switches 51 and 51' perform the same function and are spaced for the convenience of the operator. i

The voltage of the testing circuit can be regulated in accordance with the *wire or conductor to 75 be tested by the voltage tap switch 56 0f th Sec ondary circuit 59 of the testing transformer 68. After the apparatus has been threaded as shown in Fig. 1, it is only necessary to operate the switch 6|. shown as the push button type, which volts to the primary winding 66 of the testing transformer 68.

The coil 61 of the fault relay 68 is connected in series with the are holding lamp 68, which lamp merely acts as a resistor, the resistance of which increases when carrying current, thereby limiting the current through the coil 61 of the fault relay 68 and the carbon arc gap 18 so that a voltage of volts is placed across'the carbon arc gap 18 as long as the gap is maintained. The pressing of the starting switch 6| places a sparker surge resistor 1| in series with the primary 66 of testing transformer 68 to limit the surge current and simultaneously buildup the flux in the coreo'f and the interlock contacts 65, thus supplying 118 the testing transformer 68. Upon release of the 6 push button switch 6i the sparker surge resistor 1| is shunted by the same, thus applying the en-' tire 110 volts to the primary windings 66 of the testing transformer 68. The coil 1201 the motor contactor 13 is connected in multiple with the primary 66 of the testing transformer 68 through the normally closed contacts of the coiler brake release switch 14 shown in the form of a foot operated switch, and the motor contactor series resistor 15. Upon energizing the coil 12 of the motor contactor 13, the contacts 16 close, thus releasing the solenoid operated brakes of the supply reel I8 and the motor 31, starting the motor 31 to draw the wire or conductor ll through 23 of the testing unit or electrode 28 c'ausedby: the high voltage current jumping across. the gap caused by the defect between the wire orconductor II and the testing unit or electrode 28. The defect or fault in the testing unit-or electrode 28 causes a load to be applied to the secondary winding- 58 of the testing transformer 68 breaking down the carbon arc gap 18. This arc, as mentioned previously, is maintained bythe 110 volt,

ate, and energizes the coil 88 of the stop relay 8| which shunts the coil 12 of the motor contactor 13 and locks itself through the contacts 64 of the sparker contactor '63. The shunting of the coil 12 of the motor contactor 13 de-energizes the same, thus stopping the motor 31. The stop a relay 8!, when it operates, connects the coil 82 of the sparker cut-oifmechanism 83 to the line through the contacts 64, 84-of the sparker contactor 63, thus'causing the sparker cut-ofl mechanism 83 to shunt the coil 62 of the sparker contactor 63, de-energizing the same, and consequently de-energizing the testing transformer 68.

- or conductor II through the apparatus contactor I3 and energizes ter wheel 82, indicating lock circuit, which releases the To locate the exact position of the defect or I fault in the wire that has caused the apparatus to stop as described above, it is necessary to pull the wire or conductor II through the apparatus manually with the motor stopped, but maintaining a testing voltage in the testing circuit so that when the defect or fault passes into the distributor 82, a sparking will occur and the fault or defect is readily disclosed for repair or removal of a section of the wire. The operator, to prepare the apparatus for this manual operation, opcrates switch [4, disclosed as foot operated, which breaks the circuit of the coil 12 of the motor the coil 88 of the coiler brake relay 81, which causes the solenoids of the supply reel I8 and motor 31 to be energized to release the brakes. Simultaneously with release of the brakes the coil 88 of the sparker auxiliary contactor 89, connected in multiple with the coil 86 of the brake relay 81, is energized to close the sparker auxiliary contactor 89 contacts 98. The surge resistor M of the sparker auxiliary contactor 89 is permanently connected in series with the primary windings 66 of the testing transformer -88,'thus limiting the surge current when starting the flux in the transformer core and at the same time applying sufliclent voltage to the wire or conductor II to permit location of the fault or defect, The operator, while holding switch I4 in operating position, turns coiling reel 35 by hand until the defect or fault indicates by sparking at the distributor 82.

The counter mechanism 25, as described above, will stop the apparatus after a predetermined length of wire or conductor II has been tested and coiled. In Fig. 2 of the drawings the counthe length of wire in units of 100 ft., cc-operates with two contact brushes 93 and 94, while the counter wheel 95, indicating the length of wire in units of 10 feet, co-operates with a single brush 9G. The contact segments on these wheels 92 and95, adapted to contact with the brushes, are connected electrically through their common shaft 91, which is grounded to the frame of the apparatus. The counter mechanism, when the segment of wheel 95 is rotated to contact with brush 98, as shown in Fig. 2, will stop the apparat These segments complete the counter circuit and the coil 53 of the length relay 54 is energized, and the indicating length signal lamp 3| is operated. The contacts 98 of the length relay 54 look through the normally closed contacts 99 of the length interlock relay 58. The contacts I88 of the length relay connect the coil 88 of'the stop relay 8| to the line to stop the apparatus. The contacts I8I of the length relay 54 connect the coil 55 of the length interlock relay 56, and when the counter is rotated by the drawing of the wire by the operator to complete the coil, the contact segment of the counter wheel 92 .will ground the brush 94, thus energizing the coil 55 of the interlock relay 58? opening the lengthrelay interlength relay '54. This then de-energizes the coil 55 of the length interlock relay 58 to restore both relays to their 1- and apparatus for normal positions, preparing the apparatus for testing and forming another coil.

If a supply reel I8 is provided with slightly more wire or conductor II than is necessary for a coil of predetermined length as the exhaustion of the reel is about to be approached, it isgqdesirable to increase the length ofj .,the coilg without stopping the apparatus as would-happen if the counter mechanism were perfi'iitf u function. To prevent the counter mechanis from operating to stop the apparatus, the counter release button I82 is press'ed,'j which opens the counter transformer 5| primary circuit, preventing its stopping the apparatus.

At times it may be desirable to coil thewire without supplying a test voltage to the testing unit 28 and distributor 32, and to accomplish this it is only necessary to open switch I83, which prevents excitation of the testing transformer 59.

When an extremely defective reel IQ'Of wire or conductor II is encountered, it can be run through the apparatus without automatically stopping the apparatus for repair or removal of the faults or defects by opening switch I84, which opens the circuit to the coil 88 of the stop relay 8|. Switch I83 may then be periodically opened and closed manually as the wire runs through the apparatus until the insulation quality appears to be sufficiently better to warrant automatic operation.

Suitable safety devices and indicating means are provided in the apparatus such as the indicating lamp I85 connected into the circuit of transformer 48 and the indicating lamp I86 connected into the circuit of the testing transformer 59, as well as safety switches I81 and I88 on the door for the enclosure 4| for the electrical apparatus and the coiling cover or guard 34 respectively.

While the invention is illustrated and described more particularly with reference to a method of testing insulated electrical wire or conductors, the invention is not confined thereto but is'intended to cover any other uses or modifications within the scope of the appended claims.

What is claimed is:

1. In a testing apparatus, electrically operated power means for passing an insulated conductor through the apparatus, a testing transformer for impressing a testing voltage upon said insulated conductor, a contactor connected to said trans-- former, a contactor for operating said power means, and means for automatically operating said contactors in sequence whereby the testing voltage is impressed upon the insulated conductor in advance of the energizing of the power means.

2. In a. testing apparatus, electrically operated power means for passing an insulated conductor through the apparatus, electrical means for testing the insulation of said conductor as it passes through the apparatus, and electrically operated means for initiating the operation of said testing means and subsequentlyand automatically initiating the operation of said power means.

3. In an automatic testing apparatus for insulated conductors, the combination with electrically operated driving means for passing an insulated conductor through the apparatus, elec trical means for testing the insulation of said conductor as it passes through the apparatus, a

locating means connected to the testing means,

means for said driving means, and elecmeans.

4. In an automatic combined testing and meas- 7 uring apparatus for insulated conductors, the

combination with electrically operated driving means for passing an insulated conductor through the apparatus, electrical means for testing the insulation of said conductor as it passes through the apparatus, and measuring means electrically connected to said power means, of control means automatically operated after a predetermined 1 length of conductor has passed through the measuring means and also whenever a change in the insulation of the conductor appears in the testing means 'to cause stopping of power supply to and braking of the driving means and thereafter disconnecting the testing means, and means for operating the testing means and thereafter releasing the control means whereby the conductor can be passed through the apparatus manually and under test.

5. In a testing apparatus, electrically operated power means for passing an insulated conductor through the apparatus, electrical means for testing the insulation of said conductor as it passes through the apparatus, and a unitary electrically operated means for initiating the operations of said testing means and said power'means in se- (meme.

6. In a testing apparatus, electrically operated power means for passing an insulated conductor through the apparatus, electrical means for testing the insulation of said conductor as it passes through the apparatus, and a unitary electrically operated means for initiating the operations of said testing means and said power means so that said power means will not operate until after initiating operation of said testing means.

7. In a testing apparatus, electrically operated power means for passing an insulated conductor through the apparatus, electrical means for testing the insulation of said conductor as it passes through the apparatus, and a single switching mechanism for sequentially initiating the operations of said testing means and said power means so that the initiation of the power means depends upon the initiation of the testing means.

8. In a testing apparatus, electrically operated driving means for passing an insulated conductor through the apparatus, braking means for said driving means, electrical means for testing the insulation of said conductor as it passes through the apparatus andv electrically operated means for initiating the operation of said testing means and subsequently and automatically releasing the brakes and initiating the operation of the driving means.

WALTER. M. HILL. 

